Field of the Invention
The present invention generally relates to a driving circuit having a built-in-self-test function; particularly, the present invention relates to a source driving circuit which has a judgment mechanism and can increase a driving efficiency.
Description of the Related Art
Generally, a source driving circuit of a display module utilizes an additional test module to test the accuracy of an output voltage. For instance, the test module includes a plurality of test pins, and the test module has a highly-accurate voltage value to determine pass or fail in the output voltage of the driving circuit.
In practical applications, in order to get accurate voltage values, the driving circuit requires enough time to settle in each pixel period, and the settling time depends on a loading level of the output end of the circuit. In addition, when the circuit finishes the settling operation, the test module requires enough time for computing. In other words, the driving circuit requires enough settling time and computing time to execute settling and computing sequentially; however, it yet decreases the test efficiency of the test circuit.
It is noted that the amount of the test pins of the test module is almost (or at least) one thousand pins, and the accurate value of the voltage must be less than 1 mV. However, more pins indicate more material cost of the driving circuit; in addition, the highly-accurate value of the output voltage depends on the performance of the test circuit. A larger amount of pins invisibly increase the hardware cost of the test circuit and the loading of the test time.
For the above reasons, it is desired to design a display driving circuit for decreasing the test time and increasing the voltage accuracy.